Seismic risk management of piles in liquefiable soils stabilised with cementation or lattice structures

Rohollah Rostami,Nicholas Hytiris,Slobodan B Mickovski,Subhamoy Bhattacharya

doi:10.1680/jgere.18.00029

Rohollah Rostami, Nicholas Hytiris + Show 2 more

Open Access

https://doi.org/10.1680/jgere.18.00029

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Abstract

Liquefaction is an important seismic hazard that can cause extensive damage and high economic impact during earthquakes. Despite the extensive research, methodologies and approaches for managing liquefaction for pile-supported structures, failures of structures due to liquefaction have continued to occur to this day. The main aim of this paper is to develop a simplified methodology for reducing potential structural damage of structures founded in soils susceptible to liquefaction. In order to implement a successful remediation technique, the current methods for pile failure in liquefiable soils and remediation schemes of earthquake-induced liquefaction are critically reviewed and discussed. Cementation and lattice structure techniques for reducing liquefaction hazard are proposed, while numerical analysis for unimproved and stabilised soil profiles using the finite-element method is carried out to simulate the analysis of both stabilisation techniques. The results showed that both techniques are effective and economically viable for reduction or avoidance of potential structural damage caused by liquefied soil and can be used in isolation or in combination, depending on the ground profile and pile type.

Highlights

Damaging effects in pile-supported structures due to liquefiable soils were extensively observed during and after earthquakes in the past (Bhattacharya, 2006; Bhattacharya et al, 2011; Lombardi and Bhattacharya, 2012; Tokimatsu and Asaka, 1998), which put the remediation of earthquake-induced liquefaction in the focus of geotechnical earthquake engineering practice
Seismic risk management of piles in liquefiable soils stabilised with cementation or lattice structures Rostami, Bhattacharya, Hytiris and Mickovski
Numerical analyses of unimproved and stabilised soil models with cement injection and lattice structure techniques were performed to investigate their effects in liquefiable soil when subject to seismic loading

Summary

Introduction

Damaging effects in pile-supported structures due to liquefiable soils were extensively observed during and after earthquakes in the past (Bhattacharya, 2006; Bhattacharya et al, 2011; Lombardi and Bhattacharya, 2012; Tokimatsu and Asaka, 1998), which put the remediation of earthquake-induced liquefaction in the focus of geotechnical earthquake engineering practice. Through evaluation of the seismic risk and subsequent management the existing piled foundations usually achieve the desired level of safety, failures of structures due to liquefaction still occur. The response of pile-supported structures to liquefiable soils depends on the stiffness of the pile foundation, the response of the soil surrounding the pile and the soil–pile interaction effects (NEHRP, 2012). The interaction effects include the inertial loading exerted by the superstructure and the kinematic loading induced by the soil surrounding the pile (Figure 1)

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